This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Many microorganisms produce low-molecular-weight, iron(III)-specific binding compounds called siderophores to compete for iron during iron-limitation. The siderophores isolated from terrestrial bacteria and fungi and from marine bacteria show promise as biomedical agents and for control of microbial growth. To date, no iron-binding compounds produced by marine fungi have been structurally characterized. The siderophores produced by marine fungi provide an as yet unexplored source of novel bioactive compounds. The proposed project will provide the first examples of marine fungal siderophore structures. The specific aims of this project are to: 1. Screen open-ocean fungal strains for the production of iron-binding compounds under conditions of iron limitation. 2. Isolate iron-binding compounds from open-ocean fungal strains. 3. Determine the structure(s) of siderophore(s) produced by open-ocean fungi using amino acid analysis, NMR, and mass spectrometry. Involvement of undergraduate students in research is a vital component of their training and education. The proposed research will be accomplished in collaboration with undergraduate students from Northeastern State University. Students will have the opportunity to learn microbiological techniques, natural product isolation and purification techniques including solid phase extraction and reversed-phase HPLC, and structure characterization methods including amino acid analysis, fatty acid analysis, mass spectrometry, and 1D and 2D NMR.